Piston-valve.



No. www. y Patented 1an. so, |900.

F. H, CLARK.

Plsmn' vALvE.

(Application filed June 5, 1899.)

NNW STTFS PATENT OFFIC FRANK II. CLARK, OF CHICAGO, ILLINOIS.

PISTON-VALV E.

SPECIFICATION forming part of Letters Patent No. 642,085, dated January 30, 1900.

Application iiled Inno 5, 1899. Serial No. 719,450. (N0 model.)

To @ZZ whom t may concern:

Be it known that I, FRANK H. CLARK, a citizen of the United States, residing at Chicago, in the county of Cook and State of Illinois, have invented certain new and useful Improvements in Piston-Valves, of which the following is a specification.

My invention relates to that class of valves known as reciprocating piston valves, which are provided with packing-rings to practically prevent the leakage of steam from one side of the piston to the other, and particularly that class of piston-valves which are used in connection with locomotives.

The principal object of my invention is to provide a simple, economical, and efficient piston-valve; and the invention consists in the features, combinations, and details of construction hereinafter described and claimed.

In the accompanying drawings, Figure l is a sectional elevation of the valve-chest of a locomotive, showing my improved pistonvalve as it is used in connection therewith Fig. 2, an enlarged sectional view of my improved valve; Fig. 3, a cross-sectional detail taken on the lines 3 of Figs. 4 and 5; Fig. 4, a broken elevation of one of the piston-heads; Fig. 5, a broken plan view of a portion of the piston-head, showing the packing and bull rings and a portion of the valve-chest bushing in dotted outline; and Fig. 6, a detail View of one of the packin g-rin gs as it appears when spread apart.

In the art to which this invention relates it is well known that it is objectionable to have the ends of the follower-plate and spider, which form the valve-piston head and which also act as stops for the packing-rings, project out as far, or substantially as far, as the packing-rings, so that they in a measure bar the ingress and egress of the live and exhaust steam, and, further, that it is objectionable to have the rings which form the packing of the piston-head subjected underneath to either the exhaust or live steam, for the reason that the pressure of the steam on the under side develops considerable friction. It is further well known that the use of a piston-head having but a thin web or partition to separate the exhaust from the live steam is objectionable in that there is inevitably a loss of heat and condensation, due to the differences in temperature on both sides of the piston-head- The principal object of my invention,the1e fore, is to provide a piston-valve of such construction and arrangement that will remove the above-noted objections and at the same time provide a simple, economical, and eiiicient structure, all of which will more fully hereinafter appear.

In constructing my improved piston-valve I use a valve-chest A of the desired size,shape, and strength, and provided with the usual ports and passages a, a', and A', through and by which steam is admitted to and exhausted from the cylindrical pressure chamber a2. This steam-chest I prefer to provide with two cylindrical bushings B and B, in which my piston-valve reciprocates, and which are provided with two sets of peripheral openingsh, which leads to the exhaust-passage, and b', which is alternately connected with the inlet a and outlet-passages A.

To connect and disconnect the inlet and outlet passages with the port or passage leading to the cylindrical pressure-chamber a2, I provide a piston-valve having two spider or head portions C and C', connected together in one integral piece by means of a central tubular portion C2. Each of these head portions is provided with a follower-plate c and c', so constructed and arranged that they overlap the piston-heads at c2 and provide radi* ally-projecting flan ges c'`,which, together with the head portions, form annular grooves c4, having a substantially solid or imperforate inner wall or bottom portion, and act to prevent any steam-pressure from contacting the inner surface of either the bull or packing rings. The head portion of the piston-valve and the follower are provided with annular grooves in their respective contiguous faces, so constructed as to form an annular deadair space C3. From this arrangement it will be seen that when the live pressure is on the inner side of the piston-head and the exhauststeam pressure on the outer side this dead-air space efectually insulates one from the other, and thus prevents what would inevitably be a great loss of heat and consequent loss of energy.

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In order to form spaces in which packingrings may rest and efficiently permit the steam to enter or leave the fluid-pressure chamber of the locomotive, a solid bull-ring D is provided and inserted in the central portion of the annular groove in the piston-head, dividing such groove into two annular grooves, one on each side of the central portion thereof and of the bull-ring. Into each of these annular grooves or spaces are inserted transversely-split packing-rings E and E, which project slightly above the bull-ring and out and overthe flanges or stops of the head and follower portions. These packing-rings are transversely split at e inpan oblique angle, as shown particularly in Figs. 3, 5, and 6, and are in line with each other, as shown particularly in Fig. 5. They are also L-shaped in cross-section, and have what may be termed their flanged portions e extending out and over the flanges of the piston-head and follower-plate, or what might more properly be termed the stops of the piston-head and follower, so that the pressure as it enters or exhausts through the openings b and b' passes directly across the edge of the L-shaped portion and is not interfered with or restricted in any manner.

To hold the parts in place, the valve-stein II is provided with a shoulder t, abutting against one of the followers, and a projecting rod portion g', extending through the tubular portion of the piston-head and out through the other follower-plate, where it is provided with a threaded portion having a nut G2, which clamps all of the parts together.

It is highly desirable that the parts be always retained in the same position, so that the split portions e of the packing-rings may pass across and contact the surface of the bridge b9 of the valve-bushings, as shown particularly in dotted outline in Fig. 5, and thus prevent the sharp edges of the split ring from catching in the openings or ports in the valve-bushing. To accomplish this result, the bull-ring is provided with. a perforation (see Fig. 3) through which the pin H is passed and which enters cylindrical recesses in the piston-head and follower-plate. The packing-rings are notched or grooved at e4, directly across and adjacent to the slitted portions and arranged so as to engage the pins H, as shown in Fig. 3. This construction and arrangementV prevents the packing and bull rings from turning or rotating in the annular groovesand always keeps the slitted portions in position to slide on the bridge portion of the bushing. The projecting rod on the valvestem is provided with a feather g2, arranged to enter a groove in the piston-head and follower-plate, and thus prevent such parts from turning on the valve-stem.

In assembling the parts the bull and packing rings are first placed in engagement with the piston-head. The follower-plates are next bro u ghtinto position and the valve-rod passed through all of the parts and, by means of its nuts, securing them all together.

I claiml. In a piston-valve, the combination of a spider or head portion provided with a radially-extending flange or stop portion, a follower portion provided with an extending flange or stop portion forming in connection with the head portion a stepped annular groove, a continuous bull-ringhaving side flanges fitting between the first step of such annular groove dividing it into two sidestepped annular grooves, and a transverselysplit L-shaped packing-ring in each of the last-named annular grooves fitting into the steps of such grooves with theirflanged portions extending out and over the piston stops or flanges, substantially as described.

2. In a piston-valve, the combination of a spider or head portion provided with a radially-extending flange or stop portion, a follower portion provided with a radiallyextending flange or stop portion forming in connection with the head portion astepped annular groove having a solid or imperforate bottom portion,a continuous bull-ring having side flanges fitting the first step in such sidestepped annular groove dividing it into two annular grooves, one on each side of the bullring, and a transversely-split L-shaped packing-ring in each of the last-named annular grooves fitting the side steps of such grooves with their flange portions extending out and over the piston stops or flanges, substantially as described.

3. In a piston-valve, the combination of a spider or head portion provided with a radially-extending stop or flange, a follower portion provided with radially-extending stops or flanges and forming in connection with the head portion a stepped annular groove having a solid imperforate bottom portion, a bullring having its side flanges fitting into the first step of the said groove and dividing the stepped annular groove into two side-stepped annular grooves one on each side thereof, a transversely-split L-shaped packing-ring in each of the last-named side-stepped annular grooves fittingthe side steps of such grooves with their flange portions extending out and over the piston stops or flanges, and a pin engaging the bull and packing rings and the piston-head and follower-plate to prevent independent rotation of such parts, substantially as described.

4. In a piston-valve, the combination of two spider or head portions connected together in oneintegral portion by a reduced hollow cylindrical or tubular portion, a follower-plate for each head portion forming in connection therewith a stepped annular groove having a solid imperforate bottom portion and an internal chamber which provides a dead-air space, a bull-ring having side flanges fitting the first step in each annular groove and dividing it into two side-stepped annular grooves,

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one on each side thereof, a transversely-split L-shaped packing-ring in each of the lastnamed annular grooves iitting the side steps of the grooves with their flange portions eX- tending out and over the piston-flanges, a pin passed through the bull-ring and engaging each packing-ring and piston-head and follower-plates to prevent independent rotation of the parts, and a valve-stem passed through the follower-plates and piston-heads and provided with nut mechanism for securing the parts together, substantially as described.

5. In a piston-valve, the combination of a head portion provided with a radially-extending ange, an annular portion provided with a radially-extending fia-nge and forming in connection with the head portion a stepped annular groove having a solid imperforate bottom portion, a bull-ring having a flange on each side fitting the rst step of the groove and dividing the annular groove into two sidestepped annular grooves one on each side thereof, a transversely L-shaped split packing-ring in each of the last-named annular grooves Vfittin g the steps of such grooves with their flange portions extending out and over the piston-flanges, and a pin passed through the bull-ring and packing-rings and engaging With the piston-head and follower-plate to prevent independent rotation of such parts, substantially as described.

6. In a piston-valve, the combination of a piston-head portion provided with radiallyextending anges forming stops for packingrings, a stepped annular groove between the flanges, two transversely-split L-shaped packing-rings arranged in a stepped annular groove of the piston-head portion and fitting the steps of such groove and having their ange portions extending out and over the stops on the piston-head, and a pin or similaielement engaging With the piston-head and With the packing-rings to prevent independent rotation of such parts, substantially as described.

F. I-I. CLARK.

Witnesses:

THoMAs F. SHERIDAN, THOMAS B. MoGREeoR. 

